By conventional technology it is known to form one or more layers of materials on a structural part to produce properties at the surface of the structural part which are different from those of the part itself. Examples of such layers are heat-insulating layers to resist pitting and corrosion, anti-wear layers including tribological layers and scraping and run-in layers. Such layers are applied in practice, primarily, by thermal spray processes.
The disadvantage of the known processes is that in the case of structural parts of complex shape, a sufficiently uniform thickness of the layer can not be applied to the structural part except with great difficulties. In order to eliminate these difficulties, even only partially, considerable expense is necessary.